Sterile, reusable plant growth assemblies are needed to study the specific effects of biological or chemical agents, without interference from extraneous contaminants, during prolonged growth periods. Currently, reusable systems are not commercially available for growing plants under sterile conditions with the growing medium partitioned from a nutrient solution.
One currently used system of sterile plant growth apparatus and method is commonly referred to as the "glass bottle-jar assembly" Glass "Leonard" jars (Leonard, in 1944; and Vincent, in 1970), referring to a certain particular kind of jar, have been used for sterile growth purposes in several laboratories. Leonard jars have consisted generally of used beer bottles with the bottoms removed that have been inverted and filled with soil or any other plant growth medium, which is held in place by a cotton plug in the narrow mouth of the bottle. The narrow mouth of the bottle is inserted into a glass jar containing nutrient solution. A cotton wick, which penetrates and is held in place by the cotton plug and penetrates into the glass jar, facilitates the uptake of nutrient solution from the glass jar to the plant growth medium in the bottle.
The glass bottle-jar assembly has several disadvantages which include the following: (1) Because they are glass, they tend to crack and break during autoclaving, washing, and general handlingespecially when accidentally hit with another object or dropped. (2) The cut end of the beer bottle tends to be a very sharp edge, and unless etched well, often is unsafe in routine handling. (3) The bottle does not fit very well in the mouth of the jar, causing slippage and rocking of the assembly. (4) The roots of the plants grow down into the jar through the cotton plug in the mouth of the bottle, into the jar resulting in a non-uniform absorption of nutrients as well as eventual decay of the submerged roots. (5) Replacement of the nutrient solution requires opening the jar frequently, resulting in an increased chance of contamination of the nutrient solution, the roots, and the plants.
While it is important to provide systems for growing of plant seedlings under sterile conditions, when the objective of a study requires sterile growing conditions, it is also important to provide systems which are relatively simple in order to maintain plant growth with minimal attention. It is also desirable to keep the unit cost at a minimum, since most laboratories will use a large number of assemblies in their research programs.
It is well known that most plants grow best when supplied with the proper amount of moisture to their root system at a constant rate. Watering of a large number of plants, as in a laboratory, a plant store or a large office building, can be a burdensome chore. The task is further complicated because not all plants require the same amount of water during a given period of time. Some types of plants require daily watering. However, it is not always possible to water plants on a daily basis, for example on such occasions as when a person is on vacation, or when a laboratory, store, or office building is closed for the weekend or a holiday. Such neglect is often harmful to plants.
To this end, self-watering planters have been developed which include a shallow dish or water reservoir and a separate plant container or pot resting on a support elevated above the level of water in the water reservoir. A wick or other means of absorption has one end disposed through an opening formed in the lower portion of the plant container and the other end immersed in the water contained in the reservoir. The water is drawn up through the wick and into the growing medium of the pot through capillary action.
Misadventures in growing young plants are well known. These include: irregular moistening of the mass of growing medium, producing a deterioration of the roots; moistening is often excessive and causes the roots to rot when the lower part of the mass of the growing medium is bathing in the drainage water contained in the reservoir; moistening is frequently insufficient which causes the roots to wither when the reservoir evaporates too quickly. It has therefore been a sought-after objective to create and provide a better plant growing assembly, system, and method. Prior inventions include the following:
U.S. Pat. No. 4,463,522 Lindemann teaches a system and apparatus for growth of plants from sterile plant particles. An aluminum tray contains a sterilizable plant growth medium. The tray is placed in a polypropylene bag and the unit is sterilized in an autoclave. Subsequently, the tray is inoculated with a suspension of sterile plant particles. A membrane serves as a closure prevention means during autoclaving and also as a wick after closure of the bag, with one end in the plant growth medium and the other end in the bag under the tray so as to absorb any moisture collected at the bottom of the bag and return it to the growth medium.
U.S. Pat. No. 4,324,070 Swisher teaches another planter that comprises a water reservoir, lid and plant container that could be made of molded plastic, and although shown generally circular, could be any shape. The lid contains an opening for an absorbent wick.
U.S. Pat. No. 4,224,765 Song teaches a plant culture container. The individual components of the container are best seen in FIG. 4 of the patent, and consist of a base member, a top or cover, a partitioning member, a filter for the vent opening and a cover for the vent. The partition member includes a longitudinal partition wall and a plurality of transverse partition walls; compartments are defined by these walls. With the cover removed, the compartments are filled with a growth medium such as agar, water, hormone and plant food. A plant is put into the medium in each compartment and the cover placed on. The container is made of polypropylene plastic, and it is stated that the growth takes place under aseptic conditions and that the members of the container are readily cleaned and sterilized for reuse.
U.S. Pat. No. 4,121,525 Courtis teaches a method of aseptically sowing small seeds in a sterile flask with a growth medium and closed by a puncturable resealing membrane as a closure. Seeds are sterilized and passed through the membrane by a hypodermic syringe.
U.S. Pat. No. 4,027,427 Stoller et al. teaches a sterilizable plastic bag for growing mushroom spawn. The bag contains a suitable substrate and is sterilizable. A collar is threaded with a lid. the lid has an in turned lip that mates with the rim of the collar. A filter is held between the rim and the lip. This whole closure is reusable. The bag can be made of polyethylene, nylon or polypropylene.
U.S. Pat. No. 3,958,366 Meyers teaches a flower pot manufactured from a variety of materials including polyethylene or polystyrene as the preferred materials. There is a bottom container for holding water and an upper container for potting soil. The containers are fitted so as to be detachable. There are a plurality of wick tubes extending into the bottom container which are open at the bottom and contain wicks that extend into the top container.
U.S. Pat. No. 3,676,953 Delogne teaches a plant box of porous material such as asbestos cement. The container is filled with mould or compost and rests on a double perforated plate. The mould is humidified with wicks extending into a chamber below the perforated plates containing water. The mould is covered with a gravel layer.
U.S. Pat. No. 3,199,250 Sawyer teaches a seed growth apparatus which includes a tray structure. The tray structure is made of plastic and forms a support for a container. A shoulder of the tray engages the upper rim of the container. Seeds are wetted as a result of a ring made of blotter paper and supplied with liquid from a wick. A cover is provided for the tray structure.